Such as?

Healthy boundaries are important.

1. "Racist jokes are not funny," I say firmly. "I was just kidding," racist jerks protest. I don't smile. If they feel uncomfortable, they should.

2. Naked and ready for sex, I felt shocked when my former boyfriend's dog jumped on the bed and forcefully shoved his nose in my crotch. "I asked you to put that dog behind a closed door!" I told Willy. With my leg, I swept the dog off the bed onto the carpet. Willy punched me in the leg.

"You may NOT hit me!" I told Willy, jumping up. "I'm leaving." Quickly dressed and left, never to see him again.

3. Surround myself with positive people. That's a healthy boundary. Negative people drag everyone down.

I would say they do both, I understand your point. I am a firm believers in boundaries though, good fences make good neighbours and all.
I live multiple lives in part to keep"me" hidden. I have very firm barriers, limited people have my phone number or personal email addresses, few know where I live, very few get past my front door. In fact very few would walk up to it. In many ways I aspire to be like "Wonko the Sane", a character from Hitch Hikers Guide.
He has put a fence, not around his home, but around the rest of the world outside his home. His home is called, "Outside the Asylum" and the fence is to contain the asylum residents and to keep them safe.

You could look at it that way! I will put a gate on my fenced space and I will come out when I choose...when I can face with courage...that which awaits me!

Sometimes, boundaries allow a person to live their life without impediments.

Oh boy.... is there a key for that gate lock?...?

Whatever it takes to keep them at a safe distance.